Crown design fits profile for high performance.

Okuma America Corp, Charlotte, NC, has debuted its new 2-axis CNC lathe, called the Crown, to meet user requirements for quickness, power, size, and ease of use. The machine, which like the Cadet was designed and engineered in Charlotte, offers design advances including new high torque spindle motors, direct drive headstock, servodriven tool turret, and ergonomically configured machine enclosure - all on a compact 95[inches]x69[inches] machine footprint.

The Crown will replace the highly serviceable and popular Cadet 2-axis CNC lathe that has been the backbone of Okuma's early success in the US market. Some 3500 Cadet lathes have been produced since its introduction in 1991.

Okuma emphasizes that the Crown is "not a Cadet." It's a totally new machine. The company estimates that 10,000 of the Crown series will be produced through the year 2005, the production life cycle of the machine. Production of the machine is expected to be 60 per month by mid-summer with that figure approaching 80 units per month as early as next year.

The Crown is available in three models, the 10-hp Crown-E, the 15-hp Standard Bore, and the 20-hp Big Bore machine. The E Series Crown offers entry-level CNC pricing, based on a hydraulic turret system that provides station-to-station tool index times of 0.8 sec. The S-type Crown, with its all-new servodriven turret, cuts tool index times to 0.2 sec. The system features internal motor and gearing to produce high performance CNC turning. A V12 hydraulic turret is standard with the Crown-E. The Standard Bore and Big Bore models both use a V12 NC control servomotor turret.

The Crown's direct-drive headstock delivers power directly to the main spindle. As a result depending on the model selected, main spindle speeds are infinitely variable between either 75 and 4200 rpm or 65 and 3500 rpm. The machines feature tensioned ballscrew assembly powered by a direct drive system resulting in greater speed and accuracy in positioning. Machine travels in the Z and X axes are the same for all models: X axis, 7.28[inches]; Z axis, 20.47[inches]; X-axis rapid feedrate, 590.55 ipm; and Z-axis rapid, 787.4 ipm.

Machine rigidity begins with massive alloy cast iron castings and rugged boxways that are ground- and hand-scraped to provide 80% to 85% surface contact. Swing over the bed is 21.65[inches] and swing over cross slide is 15.75[inches]. Maximum turning diameter is 10.63[inches]. The turret will accommodate 12 tools with OD turning tools of 1[inch] and ID turning too of 1.58[inches]. Machine control is provided by Okuma's OSP Control System. The panel swings 90 deg from the machine face facilitating machine setup. Okuma's exclusive MacMan system streamlines diagnostic procedures to cut troubleshooting time, while the OSP's integral floppy disk drive enables operators to quickly load custom CNC machining programs authored on a conventional PC. The Crown machines sport a rounded enclosure intended to help deflect fluids and chips while facilitating operator access for routine setup and parts-removal operations.